1. Field of the Invention
The present invention relates to an air intake device to be connected to an internal combustion engine of a vehicle.
2. Description of the Related Art
As an air intake device to be connected to an internal combustion engine of an automobile, there is an approach in which a resonator formed as a closed box is connected to an intake duct to thereby reduce intake noises. The resonator is housed in a space inside a fender panel of a vehicle and is away from an air cleaner provided in an engine compartment with an engine compartment partition panel being located therebetween (for example, refer to Japanese Patent Laid Open Publication HEI8-193548).
The noise reduction effect of the above mentioned resonator depends on its resonance frequency, and the resonance frequency is changed in accordance with the volume of the resonator, the length of a communication pipe connecting the resonator and the intake duct to each other, the cross-sectional area of the communication pipe or the like. On the other hand, the intake noise of the internal combustion engine may be changed in accordance with the type of engine. Accordingly, if the internal combustion engine is varied, it would be necessary to change the volume of the resonator and/or the dimensions of the communication pipe, while the common resonator can be used for the same type of engine.
However, the space inside the fender panel of the vehicle, in which the resonator is provided, may variously be changed in accordance with the configuration of the fender panel, the structure of a suspension system and the like. Accordingly, it is necessary to change the design of the resonator in accordance with the type or the specification of the car, even if the same internal combustion engine is used therein.